Lee M S, Lee L L, Chen H Y, Wu Y C, Horng C B
National Institute of Preventive Medicine, Taipei, Taiwan.
Int J Infect Dis. 1998;3(2):64-9. doi: 10.1016/s1201-9712(99)90011-5.
Analysis of national surveillance data and a seroepidemiologic investigation were conducted to elucidate the causes and epidemiologic characteristics of a measles outbreak in Taoyuan, Taiwan, 1994.
Measles cases were identified through a national surveillance system. Reported cases and their physician or school nurses were interviewed to trace additional suspect cases and were sampled for serologic diagnosis. Measles-specific IgG and IgM were assayed. A confirmed case was defined as being positive for measles IgM test but not having received measles vaccination within the previous 3 months.
The outbreak began in Taoyuan City in December 1993 and continued to spread in primary schools and kindergartens, but caused only sporadic cases in neighboring towns. Among 42 confirmed cases, 15 (38%) were primary school children and 16 (38%) were kindergarten children. Among 24 confirmed cases with a vaccination record, 7 had one dose of vaccination, 4 had two doses of vaccination, and 13 (54%) were unvaccinated. The overall measles susceptible proportion at a kindergarten before the outbreak was 8.1% (17/209) and the overall measles cumulative incidence among susceptibles was 0.65 (11/17).
A measles vaccination coverage of 82% with the first dose at 9 months of age and 63% with the second dose (measles, mumps, and rubella) at 15 months was inadequate to block measles virus circulation in Taoyuan City in 1994. The city center, with a growing population, represents a high risk as an epicenter for measles outbreaks. Measles outbreaks may occur in a school population with 92% herd immunity.
通过分析国家监测数据及进行血清流行病学调查，以阐明1994年台湾桃园麻疹暴发的原因及流行病学特征。
通过国家监测系统识别麻疹病例。对报告病例及其医生或学校护士进行访谈，以追踪其他可疑病例，并采集样本进行血清学诊断。检测麻疹特异性IgG和IgM。确诊病例定义为麻疹IgM检测呈阳性且在过去3个月内未接种过麻疹疫苗。
此次暴发于1993年12月在桃园市开始，并继续在小学和幼儿园传播，但在邻近城镇仅造成散发病例。在42例确诊病例中，15例（38%）为小学生，16例（38%）为幼儿园儿童。在有疫苗接种记录的24例确诊病例中，7例接种过一剂疫苗，4例接种过两剂疫苗，13例（54%）未接种过疫苗。暴发前一所幼儿园的总体麻疹易感比例为8.1%（17/209），易感人群中的总体麻疹累计发病率为0.65（11/17）。
1994年在桃园市，9月龄时第一剂麻疹疫苗接种覆盖率为82%，15月龄时第二剂（麻疹、腮腺炎和风疹联合疫苗）接种覆盖率为63%，不足以阻断麻疹病毒传播。随着人口增长，市中心作为麻疹暴发的中心风险较高。在人群麻疹 herd immunity 为92%的学校中可能发生麻疹暴发。
